Sequencing of the bicistronic genome segments S7 and S9 of Mal de Rio Cuarto virus (Fijivirus, Reoviridae) completes the genome of this virus

The nucleotide sequences of genomic segments S7 and S9 of Mal de Rio Cuarto virus (MRCV, Fijivirus group II) have been determined, thus completing the entire genome sequence of the virus. These segments showed a non-overlapping bicistronic structure, as in other members of the genus. MRCV S7 ORF-1 had a length of 1086 bp and encoded a 41.5 kDa putative polypeptide, whereas MRCV S7 ORF-2 had a length of 930 bp and encoded a 36.8 kDa putative polypeptide. Proteins of 39 and 20.5 kDa were predicted for the 1014 bp long MRCV S9 ORF-1 and the 537 bp long MRCV S9 ORF-2, respectively. The terminal 5' and 3' sequences of both segments were 5'AAGUUUUU3' and 5'CAGCUnnnGUC3', respectively. Specific imperfect inverted repeats of each segment were identified. Comparison of the predicted proteins with those of related virus genome segments counterparts in maize rough dwarf virus (MRDV) and rice black streaked dwarf virus (RBSDV), showed 64.5-44.3% identities. These values are lower than those resulting from comparisons between MRDV and RBSDV. The topology of the trees obtained using the complete nucleotide and amino acid sequences of MRCV S7 and MRCV S9 was consistent with the analysis of the other MRCV segments previously published.